Box springs in use today have changed very little from those in use over the years. They include an array of coil springs enclosed in a box-like frame on whose base the springs are mounted. Although such conventional box springs have provided adequate support for a mattress, they are large and cumbersome to handle in storage and transportation or shipment, particularly from the standpoint of cost.
Moreover, it is not uncommon for a coil spring manufacturer to compress or deform coil spring units layered one on top of the other into condensed or compacted multilayered packs for shipment to the box spring manufacturer. The aforementioned step is performed by means of a press machine enabling the spring units to be compressed to reduce their dimension. The coil spring units of each pack are held in their compacted state against return to their normal or unstressed condition by means of strapping applied about the unit. The spring units of each pack being compressed, the strapping is under a great amount of tension. When the packs arrive at the place of the box spring manufacturer, it is, of course, necessary to sever the strapping around the packs in order to release the spring units for installation into the box spring. This, of course, is a dangerous step because of the high degree of tension to which the strapping is subjected by the compression of the coil springs.
As can be seen from U.S. Pat. No. 4,377,279, issued Mar. 22, 1983, one proposal has been made for providing a wire foundation unit for a box spring which unit can be shipped to the box spring manufacturer in a compact state. The manufacturer would erect the foundation wires or springs and then fix by staples, rigid struts between the wire unit and the base to permanently secure the wire unit in the erected position. The box spring manufacturing process would then be completed by providing the conventional layer of padding on the top of the wire foundation and a sheet covering or casing about the entire unit. However, once the manufacture is completed, the box spring is no longer collapsible and thus must be shipped in its expanded or full-size state to the point of retail or use whereby the same storage and shipment costs result at this point as with conventional box springs.
As will be seen below, the present invention overcomes each of the aforementioned problems.